external image moz-screenshot-5.png external image moz-screenshot-6.pngexternal image moz-screenshot-7.pngexternal image moz-screenshot-1.png Laila Abou Doma
November 23rd, 2009
Math 7Dexternal image pizza.JPG
Big idea: Scaling ratios sometimes can be helpful for calculating things.
Essential Question: When do we use percentages and when do we use ratios?


Problem3.3

A. If the pizzas at a table are shared equally by everyone at the table, will a person sitting at a small table get the same amount of pizza as a person sitting at a large table? Explain your reasoning.
The small tables get less pizza because if you test it by dividing 3 pizzas by 8 campers, you will end up with 0.375 slice of pizza per camper. And if you divide 4 pizzas by 10 campers the answer will be 0.4 slice of a pizza per camper.


B. The ratio of larges tables to small tables in the dinning room is 8 to 5. There are exactly enough seats for the 240 campers. How many tables of each kind are there?
There will be 16 large tables and 10 small tables. There are exactly enough seats for 240 campers.



Problem 3.3 Follow-up

1. How are ratios helpful in thinking about the problem?

I used ratio to find numbers of large and small tables for letter B, we scaled it up.
2. How many pizzas will the cook need in order to put four on each large and three on each small table?
We will need 64 pizzas for the large tables and 30 pizzas for the small tables. In total they will need 94 pizzas.
New vocabulary words:
ratio: a comparison of 2 quantities that tells the scale between them. Ratios may be expressed as quotients, factions, decimal, percent, or given in form a:b.

scale: the number a ratio is multiplied by an equivalent ratio.
















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